1. Field of the Invention
The present invention relates to a communication system. In particular, the present invention relates to a communication system in which equipment connected to a first network communicates with a higher-layer application connected to a second network via a gateway, and more particularly to technology for connecting a lower-layer wireless transmitter subsystem to a higher-layer application.
Priority is claimed on Japanese Patent Application No. 2011-105878, filed May 11, 2011, and Japanese Patent Application No. 2012-054341, filed Mar. 12, 2012, the contents of which are incorporated herein by reference.
2. Description of the Related Art
All patents, patent applications, patent publications, scientific articles, and the like, which will hereinafter be cited or identified in the present application, will hereby be incorporated by reference in their entirety in order to describe more fully the state of the art to which the present invention pertains.
FIG. 5 is a functional block diagram illustrating a configuration example of a communication system in accordance with the related art. The communication system includes a first network (backbone network) 10 and a second network (control network) 50.
The first network (backbone network) 10 is connected to wireless transmitters 31, 32, and 33, which are lower-layer equipment, via a backbone router (BBR) 20.
A system management device 40 connected to the first network 10 manages communication resources of the wireless transmitters 31, 32 and 33. The system management device 40 receives communication resource requests from the wireless transmitters 31, 32, and 33, and distributes optimum communication resource allocations to the wireless transmitters 31, 32, and 33.
The second network (control network) 50 is connected to an application 60, which is higher-layer equipment. A gateway device 70 is connected to the first network 10 and the second network 50.
FIG. 6 is a functional block diagram illustrating a communication path in the communication system of FIG. 5. During communication with the higher-layer application 60, the wireless transmitters 31, 32, and 33, which are lower-layer equipment, need to go through the gateway device 70.
The gateway device 70 detects all communications passing through the gateway device 70, and performs protocol conversion if necessary. It is necessary to perform communication via the gateway device 70 when encrypted communication is performed between equipment connected to different layers. Thus, it may be impossible to secure end-to-end security between the equipment that performs communication.
In the communication system in accordance with the related art, for example, Japanese Unexamined Patent Application, First Publication No. 2009-260451, it may be impossible to perform direct communication between the equipment connected to the different layers when a communication partner is, for example, equipment based on International Society for Automation (ISA) 100.11a. In addition, it may be impossible to secure the end-to-end security between the equipment that performs communication.
In addition, the gateway device for performing a relay function between different layers detects all communications passing through the gateway device, and performs protocol conversion if necessary. Accordingly, when new communication is performed between the equipment connected to the different layers, the gateway device needs to handle the new communication.